Abstract
The hydrotalcite-like compound [Mg2Al(OH)6]NO3·nH2O (shorted as MgAl–NO3) was intercalated with the chelating agent ethylenediaminetetraacetic acid (EDTA) and N,N′-1,2-ethanediylbis-1-aspartic acid (EDDS) by anion exchange to uptake heavy metal ions (Cu2+, Pb2+) from aqueous solutions. These layered double hydroxides (LDHs) synthesized in this work were used to adsorb Cu2+ and Pb2+. The amount of Cu2+or Pb2+ adsorbed at different pH, temperature, and the dosage of adsorbent was determined by atomic absorption spectrometry (AAS). The structure, the composition and the surface properties of precursor-LDHs and intercalated-LDHs (intercalated with the chelating agents) were characterized by chemical analysis, Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD) and a physical adsorption analyzer. Comparative experiments were carried out with commercially available LDH adsorbent (i.e., Kyowa DHT-4A). The adsorption behaviors of the MgAl–LDHs for Cu2+ and Pb2+ in aqueous were investigated by applying the adsorption results to the Freundlich isotherms model, and the data were well fitted by the model. The results suggested that MgAl–LDHs synthesized in this work could be suitable as sorbent materials for the adsorption and removal of heavy metal ions from aqueous solutions.
